docstr: Add a layer to the network.
  
  Parameters
  ----------
  layer : Layer
      the layer to add to the network
docstr_tok: ["Add","a","layer","to","the","network",".","Parameters","--","--","--","--","--","layer",":","Layer","the","layer","to","add","to","the","network"]
code: def add_layer(self, layer):
      """
      Add a layer to the network.
  
      Parameters
      ----------
      layer : Layer
          the layer to add to the network
      """
      layer_id = id(layer)
      self.__layers_by_id[layer_id] = layer
      self.__graph.add_node(layer_id)
  
file_path: OMLT/src/omlt/neuralnet/network_definition.py
imports: import networkx
  from omlt.neuralnet.layer import Layer
label_desc: Use image node_id 2 for calling the NetworkDefinition obj's underlying member method code with example usage: obj.add_layer(layer) without return types